The U.S. Department of Veterans Affairs was accused Monday in a lawsuit of "shameful failures" in providing medical and mental health care to injured service members returning from the wars in Iraq and Afghanistan.

The lawsuit against the VA, filed Monday in federal court in San Francisco, does not seek monetary damages. Rather, it is designed to stop the VA from systematically denying what it asserts are valid claims filed by injured veterans.

The suit is proposed for class-action status on behalf of hundreds of thousands of veterans. It contends the VA failed to provide prompt disability benefits, failed to add staff to reduce wait times for medical care and failed to boost services for post-traumatic stress disorder.

The lawsuit also accuses the VA of deliberately cheating some veterans by allegedly working with the Pentagon to misclassify PTSD claims as pre-existing personality disorders to avoid paying benefits. The VA and Pentagon have generally denied such charges.

Symptoms of the disorder, the suit says, include intense anxiety, persistent nightmares, depression, uncontrollable anger and difficulties coping with work, family and social relationships.

The complaint seeks to represent between 320,000 and 800,000 veterans of the Iraq war who lawyers say are at risk of having PTSD. Ultimately, a federal judge will have to decide whether the lawsuit is properly deemed a class action that adequately represents them.

As of March 31, roughly 52,375 Iraq veterans were evaluated at VA facilities for suspected PTSD, according to an internal quarterly VA report released Monday to the Associated Press.

Meanwhile, the VA’s backlog of disability payments is between 400,000 and 600,000, with delays of up to 177 days to process an initial claim and an average of 657 days to process an appeal. Several congressional committees and a presidential commission are now studying ways to improve care.

VA spokesman Matt Smith said Monday he could not comment on a pending lawsuit.

"Through outreach efforts, the VA ensures returning global war on terror service members have access to the widely recognized quality health care they have earned, including services such as prosthetics or mental health care," Smith said.

The lawsuit comes amid intense political and public scrutiny of the VA and Pentagon after reports of shoddy outpatient care of injured soldiers.

VA Secretary Jim Nicholson abruptly announced last week he would step down by Oct. 1 to return to the private sector. He has repeatedly defended the agency during his 2 1/2-year tenure while acknowledging there was room for improvement.

More recently, after high-profile suicide incidents in which families of veterans say the VA did not provide adequate care, Nicholson pledged to add mental health services and hire more suicide-prevention coordinators.

Included as defendants in the suit are Nicholson, several other ranking VA officials and Attorney General Alberto Gonzales. The named plaintiffs are Veterans for Common Sense and Veterans United for Truth.

Information from the Associated Press and Los Angeles Times was used in this report.